# Search A 2D Matrix II Problem

## Description

LeetCode Problem 240.

Write an efficient algorithm that searches for a target value in an m x n integer matrix. The matrix has the following properties:

• Integers in each row are sorted in ascending from left to right.
• Integers in each column are sorted in ascending from top to bottom.

Example 1:

``````1
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Input: matrix = [[1,4,7,11,15],[2,5,8,12,19],[3,6,9,16,22],[10,13,14,17,24],[18,21,23,26,30]], target = 5
Output: true
``````

Example 2:

``````1
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Input: matrix = [[1,4,7,11,15],[2,5,8,12,19],[3,6,9,16,22],[10,13,14,17,24],[18,21,23,26,30]], target = 20
Output: false
``````

Constraints:

• m == matrix.length
• n == matrix[i].length
• 1 <= n, m <= 300
• -10^9 <= matrix[i][j] <= 10^9
• All the integers in each row are sorted in ascending order.
• All the integers in each column are sorted in ascending order.
• -10^9 <= target <= 10^9

## Sample C++ Code

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class Solution {
public:
bool searchMatrix(vector<vector<int>>& matrix, int target) {
int row = matrix.size();
if (row == 0) return false;
int col = matrix.size();
if (col == 0) return false;

int l, r, m, pos;

for (int i = 0; i < row; i ++) {
l = 0, r = col-1;
while (l <= r) {
m = (l + r) / 2;
if (matrix[i][m] == target)
return true;
if (matrix[i][m] < target)
l = m + 1;
else
r = m - 1;
pos = m;
}
if (matrix[i][pos] == target)
return true;
}
return false;
}
};
``````